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来源：BBC EARTH
10 animals with pre-historic roots
By Nickie Latham
Ever since the first discovery of dinosaur fossils, people have been captivated; wondering what life would be like if prehistoric animals and humans co-existed. Who isn’t gripped by the thrilling concept of a giant lizard predator chasing them down the street? Or merely by being able to wave at a passing Stegosaurus?
That said, humans already share the planet with species that are just as old as dinosaurs and others that are directly descended from them. Some haven’t changed much over the past tens of millions of years, whilst others are practically unrecognisable.
史前溯源的十种动物
尼克•拉瑟姆
自第一次发现恐龙化石以来，人们就被迷住了，想知道如果史前动物和人类共同存在，会是一种怎样的生活。谁没有被摄魂勾魄的想法吸引住呢：一只食人畜，巨大的蜥蜴在街上追逐他们，要么，剑龙路过时，只是向它挥挥手。
那就是说，人类已经和恐龙一样的古老物种以及直接源自它们的后裔的物种一起共享这个星球，有些过去千万年都没大的变化，有的则完全不相认了。
1. Crocodiles
This is what you came for: big, scary reptiles, right? Well, crocodiles share a heritage with dinosaurs as part of a group known as archosaurs (“ruling reptiles”), who date back to the Early Triassic period (250 million years ago). The earliest crocodilian, meanwhile, evolved around 95 million years ago, in the Late Cretaceous period. Modern day crocodiles descended from prehistoric alligators such as Deinosuchus; low to the ground water-dwelling predators with a long snout, a powerful tail and lots and lots of teeth.
Interestingly, aside from crocodiles, the only other archosaurs known to have survived into the modern era are birds. This means that crocodiles are closely related to the ducks in your local pond, so be careful the next time you go to feed them (just in case).
1.鳄鱼。
这就是你为什么而来，可怖的大型爬行动物，对吗？ 是的，鳄鱼和恐龙共享作为初龙（统治的爬行动物）的一部分遗产。初龙追溯到三叠纪早期（2亿5千万年前）而同时，最早的鳄鱼大致在9千5百万年前的白垩纪晚期就已进化而成，现代鳄鱼源自史前短吻鳄如恐鳄的后裔，这些在地下水中生活的肉食者，长有长长的鼻子，强有力的尾巴，以及很多很多的牙齿。
很有趣，除了鳄鱼外，唯一幸存于现时代的初龙是鸟类。这意味着鳄鱼与你当地池塘里的鸭子关系密切。这样，下次喂它们时你得小心（以防万一）。
2. Cassowaries
Judging by its giant, claw-like feet alone, it’s easy to see why people think this giant bird is directly descended from dinosaurs such as velociraptors. They are the third largest bird species in the world and have been known to attack humans. These creatures can be found in northern Australia, Papua New Guinea and Indonesia, and have signature blue necks. Some fun facts for you: they produce green eggs and are also really good swimmers.
One of the other characteristics that may link the cassowary to dinosaurs is their casque – the leathery crest on their heads from which their name is derived (“kasu” means horned in Papuan, while “weri” means head). The use of this quiff-like appendage is a topic of some debate. Some scientists believe it can be used to reduce heat1, while others suggest it’s used to help the cassowary achieve its booming call2, which can hit frequencies that are too low for humans to hear.
2.食火鸟
从它硕大的爪子一样的脚来判断，很容易看到为什么人们认为这种巨鸟就是直接来源于像迅猛龙一样的恐龙。它们是世界上的第三大鸟类 并且知道会攻击人类。这些生物在澳大利亚北部，巴布亚新几内亚和印度尼西亚都找得到，并且有标志性的蓝色颈脖。对你来说，有一些有趣的事：它们产一种绿蛋，并且实在说来，也是很会游泳的。
可以把食火鸟和恐龙联系在一起的特征之一是它们的盔突——它们头顶上的坚硬的冠羽，它们的名字就源于此（kasu在巴布亚语的意思是“有角的”，而weri的意思是“头”）。使用这个头发一般的附属物是一个有争论的话题。有些科学家认为它可以用来降低热量，而另一些科学家则认为，它可以帮助食火鸟发出低沉而有回响的叫声，这种叫声产生的频率很低，人类听不到。
3. Tuatara
Here is a similarly remarkable beast, and the sole survivor of a genetic lineage that originated in the early Triassic. Tuataras are members of the reptile group Rhynchocephalia, which blossomed into full diversity between 240 million and 60 million years ago. They live in the islands off the coast of New Zealand, feeding on beetles, spiders, and snails, as well as small birds that they decapitate with their saw-like teeth. Tuatara can live to be around 100 years old and operate surprisingly well in low temperatures.
They may be commonly referred to as a living dinosaur, but to illustrate just how genetically isolated tuataras have become as a species, let’s look at some statistics.3 Among the animal grouping “amniote vertibrates”, there are 30,000 modern species divided into six major groups: birds (at least 15,845), lizards and snakes (10,078), mammals (5,416 species), turtles (341), crocodilians (25), and, erm, tuatara (1).
3.楔齿蜥
这是一种同样不同寻常的兽类，基因血统中的唯一幸存者，起源于三叠纪早期。楔齿蜥是喙头目中爬行类动物的成员。喙头目在2亿4千万年到6千万年之前，演化出完全多样化的动物。它们生活在新西兰海岸的小岛上，以甲壳虫，蜘蛛和蜗牛为食，它们还吃用锯齿状的牙齿杀死的小鸟。楔齿蜥大致可以活到100岁，在低温下生活良好，这令人称奇。
一般说来，它们可能被称作是活着的恐龙。但为了说明基因孤独的楔齿蜥是如何成为一个物种的，就让我们来看一看一些统计数据。在“羊膜变性动物”的动物类别中，有30,000种现代物种分成六大类：鸟类（至少15.845种），蜥蜴和蛇（10,078种），哺乳动物（5,416种），乌龟（341种），鳄鱼（25种），大蜥蜴（1种）
4. Sharks
In a way, it’s an insult to sharks to consider them modern day dinosaurs because they’re much older. Their ancestors evolved into recognisably shark-like shapes over 450 million years ago, during the Silurian period. They have survived every major extinction event since the seas were filled with Trilobites. By contrast, dinosaurs are just a flash in the pan.
With a lineage this lengthy, the scope for diversity4 in terms of their make-up and appearance is huge. As with many of the species in this list, there are giants lurking in the shark family tree, such as the Megalodon. And while we may think that hammerhead sharks are odd, their T-shaped heads are nothing compared to the dinner plate sized, spiral-shaped tooth structure of the Helicoprion, or the anvil-shaped dorsal fin of the Stethacanthus. Some species of shark even developed the ability to glow in the dark, which would have made Jaws a very different film, visually speaking.
4.鲨鱼
在某种程度上，认为鲨鱼就是现代的恐龙是对鲨鱼的大不敬，因为它们要古老得多。它们的祖先在4亿5千万年前的志留纪就进化成了可辨认的鲨鱼形状的样子，自海洋有三叶虫以来，它们在每次大灭绝事件中都幸免于难。相比之下，恐龙只是大地上一瞬间的闪光.
该血统极其漫长，就它们的构成和外表来看，多样性的范围是巨大的，就这一清单的许多物种说来,大型鲨鱼就潜藏在鲨鱼的家庭树上，像巨齿鲨.虽然，我们觉得锤头鲨很是奇怪，但是它们的T形头部与直升机餐盘大小的螺旋形样的牙齿结构，或者与胸脊鲨的砧状背脊比较起来，就算不得什么。有些鲨鱼种类甚至进化得具有在黑暗处发光的能力。从视觉上讲，这使得《大白鲨》成为了一部完全不同的电影。
5. Lizards
While they share a reptilian ancestry that goes back millions of years – and have many common genetic traits, such as the laying of eggs – lizards and dinosaurs went on to follow separate paths of development. This is most evident when you consider their legs. If you imagine any of your favourite dinosaurs, their legs point straight to the ground, like those of horses or humans. By contrast, lizards and crocodiles have legs that sprawl out to the side.
In fact, for all that dinosaur means “terrible lizard”, lizards are only a distant relation to any archosaurs, having split from their common ancestry when they first emerged in the Late Triassic. They – and their snake cousins, under the banner of squamates – went on to adapt and change, resulting in more than 10,000 living species and hun-dreds of now-extinct ones. Depending on circumstance, lizards have had the time to develop a breath-taking arsenal of abilities; swimming, gliding, scaling trees and hanging from ceilings, climbing sheer surfaces, walking on water and losing and re-growing their own tails. This extreme adaptability is almost certainly the key to their survival in the face of several significant extinction events.
5.蜥蜴
虽然数百万年前，它们拥有爬行动物的共同祖先，还拥有许多共同的基因特点，例如产蛋，但蜥蜴和恐龙都沿着各自不同的发展道路前进。看一看它们的腿，这是最为明显的。如果你想象你喜欢的恐龙，它们的脚就是直立在地上，像马和人一样，相比之下，蜥蜴和鳄鱼的脚向一边伸展。
事实上，尽管恐龙意味着是“可怕的蜥蜴”，但蜥蜴只是初龙的远亲，当它们第一次出现在三叠纪后期时，就已经与它们共同的祖先分离了。他们——还有它们的蛇类表亲，在有鳞动物的旗帜下——继续适应和改变，结果存活下来的物种超过了10000种，还有数百种现已灭绝的物种。根据环境的不同，蜥蜴发展出了令人瞠目的能力，游泳，滑行，上树，悬挂在天花板上，攀爬陡峭的表面，在水面上行走，失去尾巴后长出尾巴。肯定地说，在面对好几次重大的灭绝事件中，这种极端的适应性几乎就是它们幸存下来的关键。
6. Crabs
They’re not dinosaur descendants, they’re not lizards and they did not evolve into birds, but crabs deserve a special mention in this list for developing the kind of personal armoury that, pound for pound, would make an Ankylosaurus think twice.
Lobsters and other filter-feeding crustaceans first emerged millions of years before dinosaurs, and in fact the creatures we call horseshoe crabs (more closely related to spiders than modern crabs) appeared around 450 million years ago. But true crabs are a dinosaur-era phenomenon, as they arrived on the scene between 200 and 150 million years ago. They flourished so well in fact, that scientists have ascribed a name to their greatest period of diversity, during which 80% of modern crab groups evolved: “the Cretaceous crab revolution”.5 Their diversification paved the way for crabs to inhabit a wide variety of environments. This laid the groundwork for them to survive the mass extinction event that wiped out three quarters of the plant and animal species on Earth, including dinosaurs.
6.螃蟹
它们不是恐龙的后代，它们不是蜥蜴，它们也没有进化成为鸟类。但螃蟹在这一发展了个人武器的清单中值得特别提起：一叩一叩地，叫甲龙也都要考虑再三。
龙虾和其他滤食性甲壳动物第一次出现，要早恐龙几百万年。事实上，我们称作马蹄蟹的生物（比较现代蟹类，与蜘蛛有更密切的关系）大致出现在4亿5千万年前。但真正的蟹类是恐龙时代的现象，因为它们出现在2亿至1亿5千万年前之间，事实上，它们繁衍兴盛,以至于科学家给它们最伟大的多样性时期起了一个名字：白垩纪蟹类革命，该期间形成了80%的现代蟹类。蟹类的多样性为它们在各种环境中的生存铺平了道路。这为它们在大灭绝事件中存活下来打下了基础。大灭绝事件灭绝了地球上包括恐龙在内的四分之三的动植物
7. Ostriches
Ostriches, cassowaries, kiwis and emus belong to a group of large flightless birds called ratites. Their link with the dinosaurs? Ornithologist Peter Houde6, of the Smith-sonian Institution, put forward the theory that small dinosaurs evolved into small birds, some of which flew to environments where their success as a species depended on staying on the ground. He felt that ratites had evolved “backwards” into a loss of flight, otherwise there could be no explanation for their sudden appearance in vari-ous island landmasses. The reverse evolution might also explain the shaggy feathers and “reptile jaw” of the ostrich, which may have grown to its current size in order to fight off larger predators.
7.鸵鸟
鸵鸟，食火鸟，几维鸟和鸸鹋属于不能飞的大型鸟类，称作走禽。它们与恐龙有联系吗？史密斯—索尼安研究所的鸟类专家彼得•霍德提出了一种理论：小型恐龙进化成为小型鸟类，其中一些作为一个物种，飞向它们的成功依呆在地面而定的环境。他觉得走禽已经退化，失去了飞翔。要不然，无法解释它们突然出现在不同的岛屿上。这种颠覆性的进化，也可以解释全身披挂羽毛，以及长着“爬行动物”的下颚的鸵鸟，为了击退更大的捕食者，长成了现在的大小。
8. Sea turtles
Turtles are exceptionally successful as a species. They are part of the Testudine group of reptiles, including tortoises and terrapins, found on every continent apart from Antarctica, which have evolved to live on land and in both salt and fresh water. They share common ancestry with dinosaurs – having first appeared around 230 million years ago – and show remarkable resilience considering their fellow creatures are being wiped out. Turtles also survived one mass extinction at the end of the Tri-assic period that left an evolutionary space for dinosaurs to evolve, as well as the one at the end of the Cretaceous era that then wiped out the dinosaurs.
Those shells are clearly very tough, because immediately after that catastrophe, turtles began to diversify, hugely. There is some debate as to whether turtles count as archosaurs or whether they are more closely related to snakes and lizards. Dr Terri Cleary from the Museum of Birmingham explained the problem: “They probably originate from some sort of reptile that gradually expanded its ribs out and those became its shell. But we don't have that many informative transitional fossils.”7
8.海龟
海龟作为一个物种，获得成功是一个例外。它们是爬行动物中龟甲类的一部分，包括龟类和鳖类，除了南极洲外，在每一块大陆都有发现。它们已经进化到生活在陆地上，盐水和淡水中。它们和恐龙共享一个祖先，大致第一次出现在2亿3千万年之前——并且表现出了令人称羡的适应力，考虑到它们的同伴正在被消灭。海龟也在三叠纪末期给恐龙留下进化空间的大灭绝中幸存下来，还有白垩纪末期的那一次，当时灭绝了恐龙。
那些壳显然非常坚硬。因为那次灾难后，海龟立即开始了大规模地多样化。海龟是否算是初龙，或者，它们是否与蛇类和蜥类有更紧密的联系，还有一些争论。伯明翰博物馆的特里•克利里解释了这个问题:“它们很可能源自某种肋骨逐渐扩大的爬行动物，那些肋骨就变成了壳，但我们没有那么多提供了信息的过渡化石。”
9. Chickens
The evolutionary link between dinosaurs and birds is well established, even within the not-always-scientifically-accurate world of Jurassic Park. A more recent discovery is that one particular dinosaur – the T. rex – shares some fundamental molecular structures with the common chicken.
In 2003, Jack Horner and Mary Schweitzer were attempting to extract a giant fossilized T. rex femur from a dig and had to break the bone in half to do so.8 Inside, they found molecules of the structural protein collagen, which takes different forms in different animals, acting as a kind of protein fingerprint. As there was no other dinosaur collagen to work with, they cross-referenced the Tyrannosaur collagen with modern day animals, including humans, mice and salmon. The closest match was found in chickens and ostriches – two species that have surprisingly little in common, genetically speaking – with alligators coming in third.
9. 鸡
甚至在科学也不总是精确的侏罗纪公园的世界里，恐龙和鸟类的进化联系业已确立。一项更近的发现是，一种特殊的恐龙，霸王龙，和普通的鸡共享一些基本的分子结构。
2003年，杰克•霍磊和玛丽•施韦策试着从一次考古挖掘中提取一根霸王龙的巨大股骨头化石，为了提取，不得不将这根骨头一分为二。在里面，他们发现了结构蛋白胶原分子，该分子在不同的动物体内有不同的形式，是一种蛋白质指纹。由于没有其他恐龙的胶原蛋白作对照，他们将霸王龙的胶原蛋白与现代动物的作了交叉比较，包括人类的，老鼠的和鲑鱼的。在鸡和骆驼体内发现了最接近的匹配。就遗传而言，这几乎是没有相同之处的两个物种，短吻鳄排在第三位。
10. Snakes
If any animal deserves to be called a terrible lizard, it’s a snake. They have populated our nightmares for so long and taken a central role in our phobic mythologies. Even Harry Potter’s villainous Voldemort has a snake as a pet. There is, as the Beatles might put it, something in the way they move.
The snake is another species that evolved to how we know it today by getting rid of key assets – most notably legs, and several bones in the skull that prevented total mobility.9 The Creta-ceous-era marine squamate Pachyrhachis problematicus (as described by Michael Caldwell and Michael Lee in Nature) can be considered a primitive snake.10 It has an elapine slender body and mobile skull with extra joints for larger prey, but also a working pelvis and hind limbs.
Oh, and if you didn’t already find snakes creepy enough, consider this: because they have such narrow bodies, snakes have arranged their kidneys one in front of the oth-er, rather than side by side. For the same reason, snakes either predominantly favour the right lung over the left, or get by with just the one. Sleep tight!
So, the next time you find yourself watching Chris Pratt trying to do his Velociraptor-whisperer act in Jurassic World, consider how much more realistic it might be to have him face down three angry emus, or a crocodile with a grudge.
We are walking with dinosaurs all the time and we should continue to be both grate-ful and amazed that this continues to be the case.
10.蛇
如果有动物称得上是可怕的蜥蜴，那就是蛇。它们长时间地盘踞在我们的噩梦中,并且在我们骇人的神话中扮演了主要的角色。甚至《哈里•波特》中邪恶的伏地魔就有一条宠物蛇。用披头士摇滚乐队的话说，它们的行走方式出了问题。
这种蛇，通过摆脱关键的资产——最显著的腿，以及头骨中阻止充分移动的几块骨头，成为另一种进化到我们今天所知道的物种。白垩纪时期海洋鳞状动物厚针龙（如迈克尔•考德威尔和迈克尔•李在《自然》杂志中所描写的）被认为是一种原始的蛇。它有眼镜蛇一样的纤细身体，为了捕获更大的猎物，长有额外关节的可移动的头骨。还有一个用于工作的盆骨和后肢。
啊，如果你还没有发现蛇够恐怖的话，想想这个：因为蛇有很狭窄的身体，所以它们的肾一前一后排列着，而不是并排的。因为同样的原因，多数情况下，蛇或者喜欢右肺甚于喜欢左肺，或者只使用右肺。睡个好觉！
所以，当你下一次看到克里斯•普拉特在侏罗纪世界里，表演与迅猛龙耳语时。让他面对三只愤怒的鸸鹋，或心怀不满的鳄鱼，想一想该有多现实。
我们一直与恐龙同步，我们应该继续兴奋和惊讶还会继续这种情况。
NOTE
1. The cassowary's crest, 2. Cassowary call, 3. Tuatara statistics, 4. Shark diversity, 5. The Cretaceous crab revolution, 6. Evolution of small dinosaurs, 7. Origin of sea turtles, 8. Giant fossilised T. rex excavation, 9. Snake evolution, 10. The Cretaceous-era marine squamate
注释；1食火鸟的冠羽 2.食火鸟的叫声3.楔齿蜥的统计数据4.鲨鱼的多样性5.白垩纪蟹类革命6.小型恐龙的进化7.海龟的起源8.霸王龙巨大化石的挖掘9.蛇的进化 10.白垩纪时期海洋鳞状动物
标签： 史前时代
